Prevention of disturbing vibration.



A. AMHELE.

PREVENTION OF DISTURBING VIBRATION.

APPLICATION FILED FEB. 15. I913.

Patented Nov. 23, 1915.

INVENTOR: Albert AZ'CFLQZG BY zkmaz zuuamw ATTORNEYS WITN ESSES W g Jvpazv; 9+. I LCM/VIZ UNITED STATES PATENT orriorz.

ALBERT AICHELE, 01* I BADEN, SWITZERLAND, ASSIGNOR T0 AKTIENGESELLSCHAFTBROWN BOVERI & CIR, OF BADEN, SWITZERLAND.

PREVENTION OF DISTURBING VIBRATION.

To all whom it may concern."

Be it known that I, ALBERT AICHELE, a citizen of the Swiss Republic, andresiding at Baden, Switzerland, have invented certain new and usefulImprovements in and relating to the Prevention of Disturbing Vibration,of which the following is a specification.

This invention relates to the prevention of disturbing vibrationsparticularly in machines which have a pulsating torque and moreespecially in connection with vibrations which occur due to the factthat the impulse given by the torque has a periodicity substantiallyequal to or a multiple of the natural periodicity of the system whichcan vibrate, such system including not only the machine parts subjected.to the action of the impulse but also the surroundings (for example thefoundation) so far as they are so connected with the machine that amechanical transmission of the pulsating forces takes place.Thesecontinual vibrations may loosen the structure of the machine itselfand thus'cause damage, or even the working of adjacent machines andapparatus (particularly the working of direct current machines) may beinterfered with or rendered impossible altogether in consequence of thevibrations transmitted to them.

Heretofore many proposals have been made to avoid or reduce thesedisturbing vibration phenomena by various methods, either by firmlyanchoring the whole machine to a heavy foundation having a high naturalperiodicity or in direct contra-distinction thereto, by placing thewhole machine on an elastic base thereby imparting to the whole system arelatively low periodicity. In both cases the fundamental idea was tomake the natural periodicity of the vibratory system either considerablyless or considerably more than the periodicity of the pulsation. In manycases, however, it has been found that the result obtained was imperfectand unsatisfactory, as it isfrequently impossible to employ a suitablefoundation having a high periodicity of its own (for instance whenerecting marine engines or engines in the upper stories of buildings,etc.) or the elastic mounting of thewhole machine did not yield asuflicient difl'orence between the periodicity of the torque pulsationsand the periodicity of the foundation.

Specification of Letters I'atent.

Patented Nov. 23, 1915.

Application filed February 15,1913. Serial No. 748,647.

to some extent for completely or as far as possible preventingvibration.

Referring to the accompanying diagrammatic drawings, Figures 1 and 2show one form of elastic mounting for the stator of an electricalmachine according to one construction of the present invention; and Fig.3 represents a modified arrangement also applied to an electricalmachine.

In the form of the invention illustrated in Figs. 1 and 2 the statorsare mounted on ball bearings a and capable of rotation to some extent.At its lower part it carries a projection b and is connected to the baseor foundation 0 through the intermediary of springs f which may beadjustable.

In Fig. 3 a special foundation (1 is provided and between the stator sand this foundation there are placed elastic intermediate layers p. Inoperation as regards vibration the pulsating torque generally acts onthose places of the stationary part of the machine which are next to therotating part or which surround the same. More strictly speakingtherefore, it is the stator from which the vibrations emanate and aretransmitted to the casing, shaft and bearings, as well as to thefoundation and surroundings. If now as described above the vibration isto be restricted as much as possible to the stator, it is necessary todispense with a rigid connection between the stator and the otherstationary machine parts and the surroundings, and to replace the sameby a resilient or elastic. connection which permits of a relativemovement of the stator in relation to the other stationary parts. Bythis means a transmission of the vibrations to the immediate and moredistant surroundings is practically completely prevented.

In the forms shown in Figs. 1 and 2 if the stator begins to vibrate thenit oscillates a course prevent the simultaneous provision of suitablearrangements for entirely suppressing the vibrations, so that thereforein the first place the disturbing effect of the vibrations, and in thesecond place the vibrations themselves can be suppressed.

The vibration of the stator itself may be decreased or completelyprevented by selecting the elasticity and strength of the con nection insuch a manner that the time or duration of a natural vibration of thestator is considerably greater than the duration of an impulse. Thiseffect of the elastic connection may be further assisted by artificiallyincreasing the mass of the vibrating System (for example by masses to asshown in Fig. 3) by which means the duration of a natural vibration isincreased.

In the form illustrated in Figs. 1 and 2 by adjusting the springs f thenatural periodicity of the stator system can be made suitably differentfrom that of the disturbing pulsation so that disturbing vibrationscannot be transmitted to the surroundings.

As shown in Fig. 3 it may be desirable to furnish the stator with aseparate foundation and to provide the elastic insertion between thisseparate foundation frame and the foundation. By this means the weightof the vibrating system is increased by the tween the stator and thefoundation in which the connection confines the vibrations to the statorand a rigid connection between the rotor and the foundation; as setforth.

2. In combination in machines with pulsating torque a rotor, a stator, aprojection thereon, a foundation, an elastic connection between saidprojection and said foundation and a rigid connection between the rotorand the foundation; as set forth.

3. In combination in machines with pulsating torque a rotary part, astationary part concentric with said rotary part, means preventing thestationary part moving along the axis of rotation of the rotary part andmeans permitting the stationary part to move about the axis of rotationof the rotary part, a fixed abutment and means between said abutment andthe stationary part restraining this motion.

In testimony whereof, I aiiix my signature in presence of twowitnesses.

ALBERT AICHELE.

Witnesses:

CARL Gunman, AUGUST Rfioec.

